1. Technical Field
The present invention relates to a foreign matter detecting system for detecting foreign matters contained in a liquid product such as a beverage or a liquid drug and particularly, a foreign matter detecting system for examining at real time whether or not a flow of fluid running in a tubular conduit carries foreign matters.
2. Prior Art
As the applicable food sanitary laws are based on HACCP and the PL (product liability) regulations are enforced, it will be obligatory to avoid any undesired incident, such as microbial contamination or entrance of impurities, which may occur in all steps of food quality control from the production and process of food and drug products to storage, shipment, and consumption of the products and to increase the cleanliness and the safety of such products.
HACCP stands for hazard analysis of critical control points which has been developed in U.S.A. and is known throughout the world as one of the best sanitary control system methods. The HACCP is intended for evaluating the safety of products in all manufacturing processes as compared with conventional sanitary control methods where the final products are a subject to be inspected the HACCP particularly focuses on the preventive quality control in each process and consists mainly of two major sections: hazard analysis and critical control points. Any possibility of hazardous incidents such as microbial contamination which may occur in each step of the manufacturing and processing of foods and the storage and shipment of products before the end consumers is reviewed and analyzed through determining the critical control points for preventive actions and the control standards and constantly monitoring and checking the records of control whether or not the requirements are fulfilled within allowance. Also, other hazardous items are controlled by the pre-requisite program to prevent any adulteration in the process and to improve the safety quality of products.
In manufacturing and processing plants for liquid products (e.g. beverages and liquid drugs), heating and pasteurization processes are used for preventing microbial contamination in the production line and removal of impurities with cyclone separators or the like is implemented for adulteration. When the products have been packed in containers such as cans or bottles, they are visually inspected for final, before-delivery checking. More specifically, manufacturing and processing plants for liquid products such as soft drinks or fruits and vegetable juice yield a very large quantity of products by transferring liquid materials from steps of removal of impurities to tanks and then conveying them via tubular conduits (referred to as pipelines hereinafter) to a filler where a stream of containers, such as cans or bottle, are automatically filled with the mixed materials.
In such manufacturing and processing plants, the products in process may be adulterated by foreign matters which are substantially classified in the term of source into: "material impurities" contained in the materials, "environmental impurities" entering the materials not packaged, and "equipment impurities" generated in manufacturing equipment in the production line. The removal of impurities from the liquid product which are greater in specific gravity than the liquid product can be implemented by the use of a cyclone separator or the like. The impurities, which are greater in particle size than the materials can be removed by filtration. Those are common processes for removing foreign matters from the liquid products before the major process in manufacturing steps of the conventional manufacturing and processing plants as well as the final inspection and test for ensuring the safety of the products.
However, there is still potential for adulteration with impurities in the manufacturing/processing step even if the preprocess inspection and the removal of impurities from the materials have been carried out. For example, the liquid materials may be contaminated with environmental and equipment impurities while being conveyed from their respective tanks via pipelines to the filler station where they are packaged into containers such as cans. For compensation, the liquid products such as tea or milk are filtered by a fairly fine filter to remove minute particles with simplicity. Fiber matters are likely to block up a screen of the filter and may be removed by the filter with much difficulty. The material including particles of different sizes is filtered by a series of filters to remove impurities which are greater in size than the particles but equipment impurities added after the material stage will rarely be removed by filtration. Visual inspection is not applicable to the liquid product running in the pipeline and makes the removal of impurities impossible.
In practice, the liquid product including fibers and particles is examined at its material stage by visual inspectors viewing material solutions and additives in the tanks and impurities found can only be removed by manual process. While being conveyed via the pipeline to the filler station where it is packaged into containers, the liquid product is not subjected to the inspection for adulteration and the removal of impurities.